METHODS: The objectives of this large multinational observational study were to describe recent trends in these and related endpoints among adult men and women younger than 55 years of age who were hospitalized with an ACS between 1999 and 2007 as part of the Global Registry of Acute Coronary Events (GRACE) study.

RESULTS: The overall proportion of young adults hospitalized with an ACS in our multinational study population was 23% (n=15 052 of 65 119); this proportion remained relatively constant during the years under study. The proportion of comparatively young patients hospitalized with a previous diagnosis of angina pectoris or heart failure decreased over time, whereas the rates of previously diagnosed hypertension in this patient population increased. The proportion of patients developing atrial fibrillation, heart failure, stroke, or an episode of major bleeding during hospitalization for an ACS decreased significantly over time. Both in-hospital (2.1% in 1999; 1.3% in 2007) and 30-day multivariable-adjusted death rates decreased by more than 30% (odds ratio=0.66, 95% confidence interval=0.60-0.74) during the years under study. The hospital use of effective cardiac therapies (e.g. angiotensin-converting enzyme inhibitors, beta-blockers) increased significantly over time.

CONCLUSION: The results of this large observational study provide insights into the magnitude, changing characteristics, and short-term outcomes of comparatively young adults hospitalized with an ACS. Decreasing rates of short-term mortality and important clinical complications likely reflect enhanced treatment efforts that warrant future monitoring.